From: Alex Rousskov <rousskov@measurement-factory.com>
Date: Wed, 29 Jul 2015 08:54:08 +0000 (-0700)
Subject: When SBuf chop()s away everything, always clear the buffer.
X-Git-Tag: SQUID_3_5_7~9
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=66a7cb18ad835b0a2411298db1b9d6dcf7d4ae18;p=thirdparty%2Fsquid.git

When SBuf chop()s away everything, always clear the buffer.

The old code was trying to make the clearance decision without
normalizing parameters first and missed most cases as the result.

In theory, clear()ing SBuf during chop() is just an optimization
that should have no effect on correct code functionality.
---

diff --git a/src/SBuf.cc b/src/SBuf.cc
index 3789f4b018..e87df17fda 100644
--- a/src/SBuf.cc
+++ b/src/SBuf.cc
@@ -541,12 +541,18 @@ SBuf::c_str()
 SBuf&
 SBuf::chop(size_type pos, size_type n)
 {
-    if (pos == npos || pos > length() || n == 0) {
+    if (pos == npos || pos > length())
+        pos = length();
+
+    if (n == npos || (pos+n) > length())
+        n = length() - pos;
+
+    // if there will be nothing left, reset the buffer while we can
+    if (pos == length() || n == 0) {
         clear();
         return *this;
     }
-    if (n == npos || (pos+n) > length())
-        n = length()-pos;
+
     ++stats.chop;
     off_ += pos;
     len_ = n;